Facebook is preparing to launch its blockbuster initial public offering in the US towards the end of next year, a later public debut by the social networking site than had been widely anticipated, say people familiar with the company.

The IPO, expected to be one of the world’s biggest with recent private share sales valuing Facebook at more than $66.5bn, has been expected by April 2012, with persistent speculation that it could even come this year.

However, people close to the company have told the Financial Times that Mark Zuckerberg, Facebook’s chief executive, wants to wait until next September or later in order to keep employees focused on product developments rather than a pay-out.

Other other internet companies, Groupon and Zynga, have been holding back on their IPO plans amid recent market turbulence. But Facebook’s plans have been set according to internal interests, people close to the company said.

“There’s really no reason to rush a deal,” said Lise Buyer, an consultant who advised Google through its IPO. “The company doesn’t need the money. It is a little easier to focus when you’re private. They’ll go when they’re good and ready, not before.”

“There are so many things you don’t have to do until you take public shareholder money,” Ms Buyer said. “You don’t have to take investor phone calls or show up at investor conferences.”

Peter Thiel, a prominent Facebook investor, said it was generally desirable for technology companies to defer an IPO for as long as possible. He said Google set a good example by not going public for a nearly six years, until it dominated the search wars.

“It was a good competitive strategy,” he said. “And it culturally orientated people toward long-term value and not quarterly numbers.”

Google filed its first financial statements at the latest date allowed by US Securities and Exchange Commission rules, in April of 2004, then had its IPO in August of that year.

According to SEC regulations, once a company accrues more than 500 shareholders, it must file public financial results in the first quarter of the following year.

Facebook surpassed 500 shareholders in January when Goldman Sachs became an investor, meaning it will have to publish numbers by April 2012.

Companies are not obliged to go public after publishing such data but many do so in order to take advantage of market interest and momentum. Some analysts had expected Facebook would go public shortly afterwards after lifting the veil on its financial performance.

Facebook does not disclose financial results but a person familiar with the company said that its revenues were in the range of $2bn a year. However, a report on Reuters last week said the company had made revenues of $1.6bn in the first half of this year, double that of the previous year.

Silicon Valley’s talent war might also be a factor in the timing of the Facebook IPO. This has made hiring and retaining good employees difficult.

While Facebook has been faring relatively well on this front compared to its competitors, some employees are getting keen to cash out in an IPO, according to a person close to the company. Mr Zuckerberg hopes to keep such personnel on staff through next summer in order to complete certain product rollouts, this person said.